1. Field of Invention
The present invention relates to a post driver. More specifically, the present invention relates to a vibration dampening post driver for driving posts into the ground more comfortably and with less risk of injury.
2. Background Art
Fences have been used to mark territorial boundaries, prevent trespassers from entering a property, and contain livestock. These fences require that hundreds or thousands of posts be driven into the ground at regular or evenly spaced intervals. Historically, fence builders used large hammers to drive posts, though this was backbreaking—and often dangerous—work.
There have been some advances in the post driving art area. Cylindrical post driving devices, such as that shown in Hunt, U.S. Pat. No. 2,098,146—including a post tube, which is open only at the bottom of the tube, and handles on both sides of the tube—were invented long ago. In use, these post driving devices were positioned with the open end of the tube over the post, grasped at the handles, and repeatedly driven down so that the closed top end of the tube impacted the top of the post, driving the post into the ground.
However, these traditional post driving devices caused a great deal of vibration and tended to be very jarring to the hands and wrist of the user. Users of these post driving devices often experienced pain in their arms and back and typically experienced discomfort in their hands after repeated use.
More recent advances in the area included the use of springs located inside and at the top of the post tube, also known as a driver housing, to somewhat dampen the force of the blow received when the posts are driven into the ground, such as that shown in Iddings, U.S. Pat. No. 2,998,087, and Bowers, U.S. Pat. No. 5,097,912. However, these newer post driving devices with springs internal to the post tube are limited in that the size and number of springs utilized is limited, and thus the dampening ability is minimal. While better than traditional post driving devices that have little or no impact dampening abilities, even these newer post driving devices do not contain sufficient impact dampening capabilities for many people who need to drive a large number of posts. Also, the location of the dampening spring is not effective for dampening the forces transferred from the handles to the hands or wrist of the user.
Consequently, a need has long been felt for a post driving device with better dampening abilities to better cushion the jarring impact of driving posts into the ground.